During the American War for Southern Independence, the French, under Napoleon III, invaded Mexico and established a European style monarchy under a member of the Royal Hapsburg family, Maximillian. Maximillian eventually took control of Mexico and expanded it to become a regional power. Still bitter over the loss of substantial territory to the US in the Mexican-American War, public sentiment persuaded the Mexican Emperor to accept Germany's offer in the Zimmerman Telegraph, and invade the US and CS. With US resources tied up at home, Germany was able to defeat France and Britain in Europe. But the US and CS were able to defeat Mexico and establish a more friendly constitutional monarchy in Mexico. Mexico was also a valuable ally to the US and CS in WWII and the Cold War.